I have had bees in the burbs, and I've almost always placed them near a fence. If you put them facing the fence, their first flight direction is up. If the fence is 6 feet high, they will be over everyones head by the time they cross the property line. Just look around before you start working them to be sure alot of activity isn't happening in the neighbors yards. Bees don't normally look for someone to sting, but once riled up, they become a bit less choosy.
Roofs are hot, usually sloped, and far enough from the ground to make a fall something to avoid. Adding stinging insects is a recipe for.. um....As a beginner, you want access to them to be easy, not an extreme game. If you have no yard, get an observation hive. They are fascinating.